Short answer: they're all bamboo, even our native cane. "Bamboo" is a catch-all term like "tree"-most woody grasses are classified as bamboos, but there are probably hundreds of species of bamboo. Different species of bamboo can range in size from tiny plants a few inches high up to timber bamboos that are 50-60 feet tall and have culms several inches in diameter. Here in the US, we have three native bamboos: river cane, switch cane, and hill cane. We also have a lot of introduced species that have naturalized, plus scads of them that are planted as ornamentals in landscapes. Here in my area, Chinese golden bamboo can be found growing all over the place. Some of the better ones for arrows are our native canes, tonkin cane, Japanese arrow bamboo, some of the Sasa bamboos, and some of the bambusas. Some of these (like switch cane, hill cane, tonkin, and Japanese arrow bamboo) are mostly round without much of the flat areas behingd the nodes (sulcate culms). River cane is more sulcate, but you can find round river cane if you are picky cutting it-get stems from thick patches that don't have many low branches, and use the section of the stem between the ground and the first branches. The Chinese golden bamboo (fishpole bamboo) that is so common around here is really flat behind the nodes, so it's harder to make good arrow shafts from it. There's also a lot of difference in wall thickness of the stems on different bamboos, or different ages or different patches of the same species. You can google "river cane" "tonkin cane," etc. and find a lot of info and photos.
